The present invention relates to a multiplex communication system preferably installed in an automotive vehicle, and more particularly to a multiplex communication system comprising a communication bus and various measuring and/or controlling devices, such as a meter device and a door ECU, provided as nodes branching from the communication bus.
Conventionally, the multiplex communication (e.g., LAN) system is used in an automotive vehicle to connect many electronic devices to realize advanced and complicated controls through data communications between them.
However, such an integrated communication system has a weak point that even a small trouble caused in the communication bus may give adverse influence to many of the electronic devices or disable the data communication.
In view of the problems encountered in the prior art, an object of the present invention is to provide a multiplex communication system capable of suppressing the influence of the trouble caused in the communication bus.
In order to accomplish this and other related objects, an aspect of the present invention provides a multiplex communication system comprising a communication bus, and at least one communication bus disconnect control device connected to the communication bus. The communication bus disconnect control device comprises a control means for generating a communication bus disconnect signal when a trouble of the communication bus is detected. A communication bus disconnect means is provided for separating the communication bus into at least two communication bus groups in response to the communication bus disconnect signal.
Preferably, the communication bus is constituted by a plurality of separable communication bus groups. The communication bus disconnect means selectively disconnects at least one of the plurality of separable communication bus groups in response to the communication bus disconnect signal.
Preferably, the communication bus disconnect means selectively disconnects a specific communication bus group in response to the communication bus disconnect signal when the specific communication bus group causes a trouble.
Each of the plurality of separable communication bus groups may be arranged in a ring pattern
Preferably, at least one of the plurality of separable communication bus groups is an instrument panel communication bus group including a node connected to a measuring and/or controlling device provided on an instrument panel of an automotive vehicle. At least one of the plurality of separable communication bus groups is a door communication bus group including a node connected to a measuring and/or controlling device installed in a door of the automotive vehicle. The communication bus disconnect means separates the instrument panel communication bus group and the door communication bus group from each other in response to the communication bus disconnect signal.
Preferably, the communication bus disconnect control device comprises a communication bus monitor means for monitoring a condition of the communication bus. The control means stops the operation of the communication bus disconnect means when no abnormality of the communication bus is confirmed by the communication bus monitor means.
Furthermore, it is preferable to provide the communication bus monitor means in a designated one selected from the plurality of communication bus disconnect control devices. In this case, the control means of the designated communication bus disconnect control device stops the operation of the corresponding communication bus disconnect means when no abnormality of the communication bus is confirmed by the communication bus monitor means, and generates a notification signal. The control means of other communication bus disconnect control device stops the operation of the corresponding communication bus disconnect means in response to the notification signal sent from the control means of the designated communication bus disconnect control device.
Alternatively, it is preferable that the control means of other communication bus disconnect control device stops the operation of the corresponding communication bus disconnect means based on an analysis on communication signals transmitted from the communication bus.
Moreover, it is preferable that the communication bus monitor means starts monitoring the communication bus upon activation of the communication bus disconnect means.
Another aspect of the present invention provides a multiplex communication system comprising a first communication bus connecting a first node group and a second communication bus connecting a second node group. A communication line is provided to directly connect the first communication bus and the second communication bus. A driver receiver is connected between the communication line and a control section for transmitting a communication signal from the first or second communication bus to the control section. A communication bus disconnect means is provided for disconnecting the communication bus connected to at least one of first and second connecting portions. The first connecting portion connects the communication line and the first communication bus. The second connecting portion connects the communication line and the second communication bus. The control section generates a communication bus disconnect signal when a trouble of the first or second communication bus is detected. The communication bus disconnect means disconnects the troubled communication bus from the communication line at the first or second connecting portion in response to the communication bus disconnect signal.